Disposable absorbent diapers configured to be donned like pants, in that to be donned they are pulled on over the wearer's feet and up the legs rather than wrapped directly about and fastened at the wearer's lower torso like an infant diaper, have been in the market for a number of years. Such products are often marketed as “training pants” intended for children who are walking, beginning to develop independence and dress themselves, and learning to control their bodily functions so that they can transition out of diapers and into underwear. Such training pants provide a toilet-training child with an underwear-like garment that she can learn to don herself in the same manner as underpants, providing a new sense of accomplishment and independence, while still providing protection against accidents.
Similar articles are marketed in larger sizes and intended for older children experiencing childhood enuresis, or adults experiencing incontinence.
Currently marketed designs are constructed from a rectangular or hourglass-shaped precursor chassis having a liquid impermeable, garment-facing backsheet, liquid permeable, wearer-facing topsheet and an absorbent core between the backsheet and the topsheet. The chassis of the typical design will have front and rear waist regions and a crotch region between the waist regions, and respective front and rear pairs of stretch panels formed of a laterally, elastically stretchable and contractible stretch laminate, extending from each of the waist regions, with the respective front and rear panels on each side then joined together at side seams to form a pant-like structure. The stretch laminate panels at the sides provide for elastic hoop-wise expansion of the article to allow it to be pulled over body contours while being donned, and elastic hoop-wise contraction to hold the article comfortably and securely in place while being worn.
While sufficiently popular to sustain their presence in the market, current designs present at least several challenges.
Because such products are “disposable” for the consumer and the industry is highly competitive (factors that exert downward pressure on pricing), the business of manufacturing disposable absorbent pants requires large scale and production volume for success. Thus, in addition to product quality, performance, fit, appearance and consumer satisfaction, cost and material conservation are an ever-present and ever-important objective. Elastomeric materials used as components of stretch laminates are among the more expensive components of many current disposable absorbent pant designs. Consequently, inclusion of such materials to any extent that is unnecessary to provide their intended function (elastic stretch and contraction) is undesirable.
The amount of overall lateral hoop-wise expansion available in a disposable absorbent pant is affected by the lateral width of the stretch panels (i.e., the greater the lateral width of the stretch panel, the greater the amount of lateral expansion that it will provide). Thus, the respective front and rear stretch panels must be of a sufficient lateral width to provide for the amount of lateral hoop stretch required for the intended wearer to easily and comfortably don the pant. Generally, increasing stretch capability by increasing the lateral width of the stretch panels provides for easier and more comfortable donning. On the other hand, once the pant is donned and in wearing position on the wearer, contraction is required to provide a secure, neat fit and exudate containment functionality. If the stretch panels are excessively wide, they will not be stretched enough in wearing position to provide sufficient contractive securing tension, and an unacceptably loose/sloppy fit can be the result. Generally, decreasing the lateral width of the stretch panels increases the snugness, neatness and security of the fit and containment functionality. Thus, in designing stretch panels and selecting their width, competing and conflicting objectives are presented.
Further, the precursor from and rear stretch panels must have additional lateral width available to form the seams along which they are to be attached. The seams typically include a section of the stretch laminate that is relatively fixed, such that it cannot serve to provide stretch capability. Thus, in one sense, the stretch capability of the portions of the stretch laminate material (including the relatively expensive elastomeric materials) required for side seams is wasted. Considering the production volumes required for competitiveness in the market, this is not an insignificant factor.
Additionally, the typical chassis, and especially the liquid impermeable backsheet thereof, will be required to be of a certain lateral width at the front and rear waist regions in order to provide desired containment of urine or other liquid exudates, and a desired width of the envelope structure containing the absorbent core. The needed lateral width of the backsheet will take up substantial portions of the lateral waist circumference. This leaves only a smaller fraction of the overall waist band length (at the side-hip areas available for stretch panels. In order to provide the stretch capability needed to strike the balance between the need for ease of donning and a secure fit, relatively high-performance elastomeric material is needed for the stretch laminate—which is relatively expensive. Some designs have added elastically stretchable members and suitable accompanying construction to the rear and/or front waist regions to supplement waistband stretch capability. This approach, however, adds its own cost and complexity to the design.
Further, it is often desirable for a training pant to be quickly and easily removable (such as when soiled with exudates), without the necessity of having to pull the article down over the wearer's legs and feet. For this reason, it may be desirable that portions of the pant are easily separable by the caregiver or wearer at one or more defined locations, so that it can be conveniently and neatly removed. One currently available design addresses this need by providing side seams held together only by strips of hook-type fastener components engaged with a compatible receiving material, which will allow relatively easy separation along the side seam when the caregiver or wearer applies requisite separating forces across the seam. However, this approach does not help with materials savings and in some circumstances may add cost and complexity to the design. Other design approaches have employed side seams in which the respective front and rear stretch panels are permanently bonded together. Although such approaches decrease the possibility of unintended separation, they also reduce the ease of removal.
In view of the foregoing, the design needs, and costs of materials typically used to make disposable absorbent pants, a need exists for improvements that will conserve materials and improve lateral hoop-wise stretch performance and wearer/caregiver convenience.